This invention relates generally to a fabrication system for the assembly of trusses, and in particular to a truss fabrication system with extension arms forming an additional work surface.
Pre-manufactured structural frameworks, such as trusses, are widely used in the construction industry for forming roofs, wall panels, floors, or other building components because of their strength, reliability, low cost, and ease of use. The trusses are typically assembled in a factory using machinery facilitating rapid production of large numbers of trusses. The trusses are assembled, for example, on large truss set-up tables and then shipped to construction sites. Each truss includes a collection of typically wooden truss members held together by connector plates. For example, the truss members may include lower chord members, upper chord members, and web members extending between upper and lower chord members. During assembly of the truss, truss members are arranged on a truss set-up table, and connector plates having nail like projections or teeth extending from one side are placed at the intersections of the truss members with their teeth pointed toward the surface of the truss members. To facilitate efficient assembly of the truss, a gantry press is used to press the connector plates into the truss members. The gantry press includes a gantry mounting a cylindric roller and several wheels which ride on wheel guides located along opposite sides of the table. The roller travels along the table to press the connector plates into the truss members thereby joining them together.
During the assembly of trusses, two or more boards are often spliced together end-to-end to form a chord of a greater length. Connector plates are placed at the junctions of the boards and the roller travels over a set-up table to press the connector plates into the boards. The spliced chord members and the web members are then arranged in a different portion of the set-up table or a different set-up table, and connector plates are placed at the intersections of the truss members and the roller travels over the table to press the connector plates into the truss members.
During use of a truss set-up table, an operator manually places the truss members and connector plates on the truss set-up table's work-surface. This often requires the operator to reach across portions of the set-up table. Depending on the size of the set-up table, the operator may have to reach considerable distances to place the connector plates on the truss members, thus reducing worker productivity and increasing the risk of inaccurate placement of the connector plates. It would be desirable to provide a truss fabrication system with improved access to the truss set-up table. It would also be desirable to provide a gantry press that simultaneously assembles trusses in stages as the truss proceeds laterally across the work-surface of a single truss set-up table.